--On Monday, November 04, 2002 15:04:27 +0100 "Patrick M. Hausen" <hausen AT punkt 
DOT de> wrote:

Paul Bijnens wrote:

Patrick M. Hausen wrote:
>
> Seems like Oracle likes to create a lot of small ".trc" files over
> time. The filesystem in question is littered with thousands of them.
>
> Once we archived and deleted them, backup performance was back to normal.
>
> Would separate holding disk (we don't use one at all at the moment)
> help in a configuration like this? Additionally I'd suggest deleting

Probably, then your tapedrive can keep streaming (could half your
backuptime!), and amanda can do much more parallel then it can do
without holdingdisk (another doubling or more if you have many
clients).

Precisely. In all multi-client installations I run in my own network
I have holding-disks, so dumps can be run in parallel and output
buffered. But the machine in question is a one-server-client
installation that only backs up itself. And in addition it mainly backs
up one single file system.

So my question is: does a holding-disk speed up this process? I mean,
Amanda will start a dumper on the filesystem that starts filling
the holding-disk. At the same time (?) a taper will start wrtiting
the holding-disk's contents to tape. Now imagine the dumper getting
to slow for the tape ... the holding-disk won't be filled quick
enough either. Then there's a lot of seeks on the holding-disk
itself, if it's read and written at the same time.

Or is the mental picture I have about Amanda's operation incorrect?

What should happen is that dumper will write the entire dump to the
holding disk (either in one piece or in N chunksize pieces if you
specify chunksize) and then when it is done stream the entire image
to tape.
 If your holding disk is smaller than your dump then it will be
bypassed and you will be dumping directly to tape with the pauses
and reseeks you are seeing now.

Frank

Thanks,

Patrick M. Hausen
Technical Director
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